Add release notes for Beast (#647)

Author: ashtum

release-notes/boost_1_92_0.adoc

@@ -60,6 +60,20 @@ build, and was never supported by `FindBoost`.
 * boost_phrase:library[Assert,/libs/assert/]:
 ** Fix `BOOST_VERIFY` in the rare case of both `BOOST_ENABLE_ASSERT_HANDLER` and `BOOST_ENABLE_ASSERT_DEBUG_HANDLER` being defined.
 
+* boost_phrase:library[Beast,/libs/beast/]:
+** `websocket::stream` accepts close code 1014 (bad gateway).
+** `http::basic_parser` ignores connection and framing fields in trailers.
+** `http::parser` drops framing and connection-control fields carried in trailers.
+** `http::basic_parser` rejects chunked transfer-encoding in HTTP/1.0 requests.
+** `http::basic_parser` rejects `Content-Length` with `Transfer-Encoding` regardless of field order.
+** `http::basic_parser` rejects requests with a `Transfer-Encoding` that does not end in chunked.
+** `http::basic_parser` validates quoted-strings in chunk extensions.
+** `http::message::prepare_payload` rejects 1xx responses with a body.
+** `websocket::stream` rejects 64-bit frame lengths with the high bit set.
+** File operations clear the `error_code` on success.
+** The `server-flex-awaitable` example dispatches cancellation to the task's strand.
+** Removed dependency on Boost.Functional.
+
 * boost_phrase:library[CointainerHash,/libs/container_hash/]:
 ** Hashing a valueless `std::variant` instance no longer throws.